Pump for variable-speed hydraulic transmission-gears.



C. BELLENS.

PUMP FOR VARIABLE SPEED HYDRAULIC TRANSMISSION GEARS. APPLICATION FILEDNOV. 22. 191 2.

1,153,478. PatentedSept. 1 .1, 1915.

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2 SHEETS- WITNESSES 5s B LEN (7% M sYf-II INVENTOR ATTORNEYS C. BELLENS.PUMP FOR VARIABLE SPEED HYDRAULIC TRANSMISSION GEARS.

APPLICATION FILED NOV. 22. I912.

Patented Sept. 14, 1915.

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CHARLES BELLENS, OF BRUSSELS-IXELLES, BELGIUM.

PUMP FOR VARIABLE-SPEED HYDRAULIC TRANSMISSION-GEARS.

Specification of Letters Patent.

Patented Sept. 14, 1915.

Application filed November 22, 1912. Serial No. 732,894.

To all whom it may concern; 7

Be it known that I, CHARLES BELLENS, of N 0. 74 Rue Faider,'Brussels-Ixelles, Belgium, have invented certain new and usefulImprovements in and Relating to Pumps for Variable Speed Hydraulic"Transmission- Gears, of which the following is a specification.

This invention has for its object a pump.

system for variable speed hydraulic transmission gears with reverse andserves particularly to increase the volumetric efiiciency and themechanical eflicien cy of this apparatus.

In the accompanying drawing, Figure 1 is a longitudinal section througha pump system comprising a system ofv primary pump, and a secondarypump, forminga variable speed gear for a motor car. Figs. 1f to 4 arecross sections in the elements of the primary pump correspondingrespectively to lines l 2, 3, and 4 of Fig. 1, showing the arrangementof said elements. Figs. 5 to 8 are similar views of a pump running onthe first speed, according to this invention.

In these change speed gears, the engine generally drives a group ofcoupled primary pumps. The various speed stages are obtained by varyingthe volume of the liquid delivered by successively placing in circuitand cutting out of circuit pump elements constituting the primary group.Similarly the direction of running is reversedby reversing the directionofthe flow. In order to obtain these effects the delivery and suctionorifices of each of the elements of the primary pump system asheretofore employed, are controlled by by-pass obturators, as shown forexample in Fig. 1. The obturators arranged upon the delivery direct theliquid under'pressure' toward the secondary pump or pumps or else shortcircuit the pump elements upon itself; these are the obturators for thespeeds. The obturators 6 arranged upon the suction establish the workingpressure in one or other of the conduits connecting with the secondarypump or pumps; these are the reversing obturators. p

In Fig. 1 which illustrates a rotary pallet pump by way of example theobturator a for the speeds and the reversing obturator b are in positionfor furnishing forward running, the liquid under pressure actuating thesecondary pump or pumps through the conduit c or delivery chamber. Itwill be noted that this pressure the chamber 0 tends to apply theobturator a for the speeds to its seat thereby contributing to insuringa good joint but it tends to detach the reversing obturator b from itsseat and causes the liquid to leak over the entire perimeter of itsseat. Notwithstanding the utmost care in manufacture these leakages areinevitable; the contact surfaces are necessarily small, the partsare'light and cannot be locked because it is essential to operatethemwith the greatest ease by a simple hand lever and the pressures to whichthey are subjected attain 30 to 40 kg. per square cm.

If in order to obtain the four speeds for example the primary groupcomprises four pump elements similar to that illustrated in Fig. 1, allthe reversing obturators will necessarily find themselves in conditionswhich are eminently defective as regards the leakage at their perimeterwhatever their form may be, whether slide valve, clack valve, cook orthe like. In the case of the highest speed where all the pump elementsare operative the four-speed obturators will be favorably situated asregards the formation of good joints but in passing fromthe fourth tothe third to the second to the first speed the obturators of one, two orthree pump elements will reach the position d indicated in Fig. 1 inbroken lines so that they will constitute so many additional leakageperimeters. Thus 011 the first speed seven leakage perimeters will existamong the four delivery orifices and the four suction orifices.

The foregoing explanation will render it clear why automobile vehiclesin which this type of hydraulic change speed gear is fitted run underfavorable conditions on the level the liquid pressure are relatively lowand (referring to the case described above) there are four leakageperimeters. These vehicles run under conditions of very markedinferiority on hills the pressure of the liquid increase and the leakageperimeters increase also with the efi' ort to be overcome. There will-beI'ive leakage perimeters on the third speed, six on the second speed andseven on the first speed.

In order that vehicles fitted with hydraulic change speed gear may beable to negotiate hills in conditions equal to or better than thoseobtaining with gear wheel change speed devices it is essential that thevolumetric and mechanical efiicienoy of the pumps should be the maximum.In accordance with the present invention this maximum efliciency isobtained by dispensing with the obturator liable to leak and it residesin particular in the fact that in each pump of the system with theexception of a single pump reserved for reversing, the suction orifice(or the delivery orifice) is free that is to say presents no by-pass obturator and is furthermore isolated from the delivery chamber (orsuction chamber) by a solid wall.

Figs. 1 to 4 are diagrammatic sections of rotary pumps (primary pumps byway of example) showlng the elements of the system forming the object ofthe invention! These pump elements shown in Figs. 1 to 4, are coupledtogether to form a pump system as illustrated in Fig. 1.

In Fig. 1, P, P P and 1 indicate the rotors of the several primary pumpelements.

arranged within a casing and suitably mounted upon a shaft P adapted tobe driven by an engine, not shown.

6 indicates the reversing obturator of the pump element, shown in Fig.1, 0 is the delivery chamber or conduit, 71, the suction chamber orconduit, and P is the secondary pump. Figs. 5 to 8 are also diagrammaticsections showing another applicationof the system with a specialdistribution as specified and claimed in this application. It isunderstood that the pump elements shown in Figs. 5 to 8 areto bearranged in a systemsimilar to that shown in Fig.1.

In the primary group represented in Figs. 1'to'4 and embodied in Fig. 1,the element reserved for reverse running, Fig. 1, is

provided with a speed obturator 64 upon the delivery and with areversing obturator 7) upon the suction. The three other elements (Figs.2, 3 and 4) also comprise a speed obturator e f g and the suction whichis sepa- First speed 4 to 7. Second speed 3 to 6. Third speed"--- 2to 5.Fourth speed 1 to 4.

This arrangement while largely improving the running on inclines is alsoparticularly adapted for racing vehicles because on the top speed theleakages are m'Z.

Reversed running is obtained-by the re h versing obturator I) Fig. 1.When the 0bturator bis reversed theliquid passes into the other side ofthe'pump, the obturators ofthe various pump'elements assuming then thereversed positions. A single element is sufficient for all cases. Inreversed running also the leakage perimeters are reduced in the ratio of4 instead of 7 It is to be understood that when the reversing obturatorb, Fig. 1 is shifted for reversed running, the speed obturator itassumes the reversed position shown in dotted lines, the liquid thenpassing to the opposite sidezof the pump.

In order to obtain with a touring vehicle the best possible conditionsof volumetric and mechanical efiiciency the system -of pumps is combinedwith a novel distributing gear, the whole being represented diagrammatically in Figsi 5 to 8 for running on the first speed and in thiscase alsowith a four speed gear which is now required on all vehicles.The distributing gear is diiferem tiated' from such gears as hithertoconstructed by the following points: a i

(1.) As the'elements of the group of 'pri mary pumps operate idlyinstead of being" short'circuited upon themselves through the suctionchamber or pipe 71. they areshort circuited through the delivery chamber0 (Fig. 5). V a

(2.) Ihe speed obturators a e f g are dispensed with on the delivery andshifted to the suction side of the pumps'(Figs.-5, 6, 7 and 8).

(3.) Therreversing obturator b is dispensed with on the suction andshifted to the delivery ofthe single element that it controls (Fig. 8)

When the reversing obturator is shifted from the position shown in Fig;8,-to the reversed positlon, the obturator 9 also, assumes the reversedposition, and the direction of.

the flow of the liquid is reversed from that indicated by the arrows.Owing to this combination the leakage perimeters are inverted and theratios as above at the different speeds will be as follows: 7

First speed l i 1 to 7. Second speed- 2 to 6. Third speed 3 to 5. Fourthspeed 14 to 4.

7 That is to say on inclines the joint formed by-the distributing gearwill be increasingly good in'proportion as the incline is steeper andthepressure of the liquid greater like the effort required of the engines.

' The invention is applicable to 7 all by draulic transmissionswhateverthe principle or the application may be. I

It has been described by way of example as applied to a system ofprimary pumps but it is obvious that it is equally applicable tosecondary systems or groups of pumps. I In draulic the delivery chamber0 a safety valve may be provided for avoiding bursting in case of excesspressures and this valve (not shown in the drawing) may even be locatedon the solid wall i without thereby affecting the hermeticity of thesaid wall and without interfering with the pump obturators.

What I claim is:

1. A system of primary or secondary pumps for variable speed hydraulictransmission gears with reverse, comprising a series of pumps eachhaving a suction and a delivery orifice, and a suction chamber and adelivery chamber for the series ofpumps, one of said pumps having aby-pass obturator at the suction and at the delivery orifice, the otherpumps of the series each having a by-pass obturator at only one of saidorifices, the other orifice being free, and a solid wall isolating saidfree orifice from the chamber connected with the other orifice, therebyincreasing the volumetric and me chanical efliciency of the pumps inpreventing leakages.

2. A pump system for variable hydraulic transmission comprising a seriesof pump units, each having a casing and a rotor therein, a suctionorifice leading from the inlet to the rotor, a discharge orifice fromthe rotor, and a delivery chamber to which the discharge orifice leads,one of said units having a speed obturator at the discharge orifice toconnect said orifice with the delivery chamber, or to short circuit withthe inlet, and a reversing obturator between the suction orifice and thedelivery chamber, and others of the units having a speed obturator atthe discharge orifice, and a wall permanently separating the suctionorifice and the delivery chamber.

8. A pump system for variable speed hytransmission, comprising pumpunits each having an inlet chamber, a suction orifice, a dischargeorifice, and a delivery chamber to which the discharge orifice leads,and provided with'a speed obturator adjacent to one of said orifices andcommanding communication with the delivery chamber, the other orificesbeing free and there being a closed wall separating the delivery chamberfrom the inlet chamber and located at one side of the said free orifice.

l. A pump system for variable speed hydraulic transmission, comprising acasing, having an inlet chamber and a delivery chamber, a series of pumpunits each comprising a rotor within the casing, a suction orifice fromthe inlet chamber to the rotor, a discharge orifice from the rotor tothe delivery chamber, one side of the delivery chamber being adjacent tothe suction orifice and the other side adjacent to the dischargeorifice, certain of said units being each provided with a speedobturator commanding communication between the delivery chamber and oneof said orifices the other orifice being free, and a solid wallpermanently separating the delivery chamber from the inlet chamber andarranged adjacent the said free orifice.

5. A pump system for variable speed hydraulic transmission, comprisingpump units, an inlet chamber for the pump units, each pump unit having asuction orifice, and a discharge orifice, a delivery chamber to whichthe discharge orifice leads, each pump unit being provided with a speedobturator adjacent to one of said orifices and commanding communicationbetween said orifice and the delivery chamber and said orifice and theinlet chamber, the other orifice being free, and a closed wall adjacentsaid free orifice and permanently separating the inlet chamber from thedelivery chamber.

6. A pump system for variable hydraulic transmission, comprising aseries of pump units, each having a casing and a rotor therein, asuction orifice leading from the inlet chamber to the rotor, a dischargeorifice from the rotor, and a delivery chamber to which the dischargeorifice leads, one of said units having a speed obturator at one of saidorifices to connect said orifice with the delivery chamber or to shortcircuit with the inlet chamber, and a reversing obturator between theother orifice and the delivery chamber, the other pump units each havinga speed obturator at one of said orifices, and a wall adjacent the otherorifice and permanently separating the inlet chamber fromthe deliverychamber.

7. A pump system for variable speed hydraulic transmission, comprising aseries of pump units each having a suction and a discharge orifice, andan inlet chamber and a delivery chamber for the pump units, one of saidpump units having an obturator at one of said orifices to connect saidorifice either with the delivery chamber or with the inlet chamber or toshort circuit through one of said chambers, and a reversing obturator atthe other orifice, the other pump units each having an obturator at onlyone of said orifices, to connect the said orifice either with thedelivery or with the inlet chamber or to short circuit through one ofsaid chambers, the other orifice being free and isolated from the otherof said chambers.

In testimony whereof I have hereunto placed my hand at Brussels,Belgium, this 18th day of October, 1912.

CHARLES BELLENS.

In the presence of two witnesses:

F. J. LABARRY, CHAS. ROY NASMITH.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

